Exhaust port thread

[† Will]

Hello einzylinder community.
Now the rain has started again I have started to work on Lottie and get her back on the road as soon as possible.

The first 2 threads of the exhaust outlet do not look good so I am thinking of cutting the bad threads off.
The head has been welded in the past and a new thread cut.
Any advice for cutting it square please?

[† Will]

[Kurt in S.A.]

Couldn't you try dressing it up with a metric file first?  If that doesn't work, then resort to machining things.  The first few threads are really only for getting the exhaust nut started.

Kurt

[koskisolli]

Hey Will

Too bad the thread is in so bad condition..!
I would leave it as it is IF you're able to attach the exhaust nut into the head.
If not, then I would try to file the bad threads away without cutting / sawing.
When you saw it, you will risk getting a bad starting points for the thread like you probably know.

In case you want to cut it, cut it so that you'll leave couple millimetres of bad thread and file it down so you'll make sure there's a good starting thread.
I hope you get it fixed! 

[4Taktix]

Hello Will,
your threads do not look too bad to me. I'd try everything to rescue the threads, like said above (metric file, file the bad spots flat, a.s.o.)
As it is important to have the proper port length, assuming Lottie is a /3 and you have an original drawn out exhaustpipe.
(Also check the threads in your cap nut !)
You should absolutely have a look into this thread:  http://bmw-einzylinder.de/forum/index.php?topic=14471.msg197117#msg197117
and watch the pictures in answer #3, in particular the scribble sketch. (shall show a vertical cut through the exhaust-port. The piece on the left is going to become
the pipe connection to the port and to be welded to the pipe.)
Then it should get clear, what I mean.
Best Regards from Paderborn.
Sascha

[cledrera]

Will, take a look to this link: Odeon8 or the mission is not impossible

But:
I´ll think the best way for you is testing a recutting of the thread.
For that you need a screwing die 45 x 2 for testing. Danger: Expensive
Try to lend it.
If you have no chance in England near by, send me an p.m. or post it in this Fred.
There is a Forianer I know, owning such a screwing die.

And at last a tip: Check the inside of the nut please. New or old nuts offen have abherent little fins.

Clemens

[Herculestom]

Hi Will,

The thread as such doesn't look too bad. I agree with Clemens. You can nicely rework it with such a nut. Works quite well. Some hydraulic fittings have exactly this dimension (45 x 2). I'd recommend to have a chat with one of the local hydraulic repair shops for farming or earth-moving equipment. They'll most probably have an old one in the bin which might serve the purpose to clean that thread.

Good luck and regards
Tom

[† Will]

Hello again everybody.
I have been away riding my R65LS on the End2End - www.theairhead.co.uk - charity ride from Lands End to John O' Groats covering 2004 miles in total. 

Today I was able to start work again on Lottie. I re-claimed the damaged exhaust port thread using the die bought from S.Meyer and fitted the exhaust system to the machine. The tank will be replaced tomorrow and I hope she starts. If so. we'll both be ready for the trip to Cymru in a couple of weeks time. 

Thank you all for your comments and advice so far.

The cleaned thread on the spigot.



The exhaust fitted.

[Misah]

hi all,
i'm now working on a r26 Swiss blue... I had the same problem and tried now this via a dutch company..
I'm dutch too

regards
marty
http://www.becksmotoren.nl/Reparatie/TabId/1461/ArtMID/3005/ArticleID/26/Beschadigde-uitlaatdraad-reparatie.aspx